The present invention relates generally to peristaltic pumps and more specifically to peristaltic pumps used in ophthalmic surgical equipment.
Most prior art peristaltic pumps work by compressing or squeezing a length of flexible tubing (sometimes between a fixed race) using a rotating roller head. As the roller head rotates, the rollers pinch off a portion of the tubing and push any fluid trapped in the tubing between the rollers in the direction of rotation. Peristaltic pumps are widely used in medical applications because of their predictable, constant flow properties. These prior art systems, however, typically require manual connection of the pump tube segment around the rotating roller head.
Prior art peristaltic pumps using rotating roller heads also typically impart unwanted pressure pulsations. Several pulsation damping devices have been developed to address this problem (see e.g., U.S. Pat. No. 4,921,477 (Davis)).
Some prior art cassettes have tapered sections of pump tube so that the compression of the tube is more gradual and less abrupt. See for example U.S. Pat. No. 6,293,926 B1 (Sorensen, et al.). This tapering of the pump tubing has helped reduce pressure pulsations, but additional reduction is desirable.
Accordingly, a need continues to exist for a peristaltic pump that reduces pressure pulsations.